Re: PETSCII mapping?

From: Rebecca T <637275_at_gmail.com>
Date: Thu, 6 Apr 2017 01:10:02 -0400

The Wikipedia page for PETSCII [1] only marks 20 characters as not having
Unicode equivalents; 2px (light) and 3px (heavy) horizontal and vertical
bars
at various non-center positions, diagonal shading characters, and corner
characters.

I’ve done some processing to the table on [1] to filter out the missing
characters — their exact codepoints and descriptions can be found in [2].

These characters are highlighted in red in the attached image (green
characters
are also missing but are duplicates of other characters in the chart), and
marked by U+FFFD � in the compact table [3].

The box-drawing characters seem to semantically represent lines (boxes) and
the
block elements seem to represent shapes and shades; this makes $7c, $7f,
$a7,
$a8, $a9, $b6, $b7, and $b8 block elements and the rest box-drawing
characters.

[1]: https://en.m.wikipedia.org/wiki/PETSCII
[2]: https://github.com/9999years/Unicode-PETSCII/blob/master/new.txt
[3]:
https://github.com/9999years/Unicode-PETSCII/blob/master/graphic-table.txt

[image: Inline image 1]

On Wed, Apr 5, 2017 at 11:32 PM, Rebecca Bettencourt <beckiergb_at_gmail.com>
wrote:

> On 6 April 2017 at 09:44, James Kass <jameskasskrv_at_gmail.com> wrote:
>
>> Rebecca Bettencourt wrote,
>>
>> > I can put together a unified chart, with mappings to Unicode where
>> > they exist. In fact I think I'll do that. :)
>>
>> I hope you do. That would be a good starting point.
>>
>
> I'm working on it!
>
> On Wed, Apr 5, 2017 at 7:40 PM, Elias Mårtenson <lokedhs_at_gmail.com> wrote:
>
>> Do we also have to create an example font that includes these symbols?
>> That seems to be what Michael Everson did for his chess notation proposal
>> that I read recently.
>>
>
> We do have to provide Unicode with fonts, I believe. We can use an
> existing C64 font, such as Pet Me. Or, we can create a new font with
> vectorized versions of the characters.
>
>
>> Then there is the issue of what to do with the text colour and style
>> selectors. PETSCII has characters that indicate a colour change as well as
>> reverse video. At least the reverse video one is important, as it's being
>> used to construct new characters. For example, PETSCII only has a single
>> character "half block" (top part filled). The way you represent a half
>> block with the bottom part filled is to use the reverse video together with
>> the former.
>>
>> It would probably make more sense to represent the reversed symbols as
>> separate code points?
>>
>
> I would actually leave the color-change and reverse-video characters to a
> higher-level protocol.
>
>
>>
>> Regards,
>> Elias
>>
>
>

new-characters.png
Received on Thu Apr 06 2017 - 00:11:45 CDT

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